Acoustic Emission Based Damage Characterization in Composite Plates Using Low-velocity Impact Testing

Acoustic Emission (AE) based Structural Health Monitoring (SHM) systems are important for impact damage detection and characterization in composite structures. Low velocity impact events can induce internal damage without producing visual indications, compromising the materials structural performance while being very difficult to detect and assess by traditional visual inspection method. Over the years, AE sensor networks have been developed to provide real-time monitoring and detect impact events from low velocity impacts over a large area with minimal intrusion to the composite structure. Yet, most AE methods have focused on detecting and locating damage, not characterization and assessment. This paper develops a preliminary framework for characterization of damage resulting from impacts based on AE signal features. Specialized drop-weight impact experiments were designed to study two particular damage states: delamination with minimal fiber damage and fiber-breakage with minimal delamination. Impacted test panels were inspected using ultrasonic C-scans and recorded waveform signals using piezoelectric sensors were characterized to analyze damage response in the time and frequency domains with assistant parameters such as root mean square (RMS) of the waveform